how to get the archieved version of 2.79b which WON'T install?
I think what you are looking for is the portable version.

You don't say which operating system you are using so here are all versions.

https://download.blender.org/release/Blender2.79/

I am guessing you are asking about windows, you want the ZIP version, just choose between 32 or 64 bit versions